'\" et
.TH inttypes.h "0P" 2017 "IEEE/The Open Group" "POSIX Programmer's Manual"
.\"
.SH PROLOG
This manual page is part of the POSIX Programmer's Manual.
The Linux implementation of this interface may differ (consult
the corresponding Linux manual page for details of Linux behavior),
or the interface may not be implemented on Linux.
.\"
.SH NAME
inttypes.h
\(em fixed size integer types
.SH SYNOPSIS
.LP
.nf
#include <inttypes.h>
.fi
.SH DESCRIPTION
Some of the functionality described on this reference page extends the
ISO\ C standard. Applications shall define the appropriate feature test macro
(see the System Interfaces volume of POSIX.1\(hy2017,
.IR "Section 2.2" ", " "The Compilation Environment")
to enable the visibility of these symbols in this header.
.P
The
.IR <inttypes.h> 
header shall include the
.IR <stdint.h> 
header.
.P
The
.IR <inttypes.h> 
header shall define at least the following types:
.IP "\fBimaxdiv_t\fR" 12
Structure type that is the type of the value returned by the
\fIimaxdiv\fR()
function.
.IP "\fBwchar_t\fR" 12
As described in
.IR <stddef.h> .
.P
The
.IR <inttypes.h> 
header shall define the following macros. Each expands to a
character string literal containing a conversion specifier, possibly
modified by a length modifier, suitable for use within the
.IR format
argument of a formatted input/output function when converting the
corresponding integer type. These macros have the general form of
PRI (character string literals for the
\fIfprintf\fR()
and
\fIfwprintf\fR()
family of functions) or SCN (character string literals for the
\fIfscanf\fR()
and
\fIfwscanf\fR()
family of functions), followed by the conversion specifier, followed by
a name corresponding to a similar type name in
.IR <stdint.h> .
In these names,
.IR N
represents the width of the type as described in
.IR <stdint.h> .
For example,
.IR PRIdFAST32
can be used in a format string to print the value of an integer of type
.BR int_fast32_t .
.P
The
\fIfprintf\fR()
macros for signed integers are:
.sp
.RS
.TS
tab(!);
le le le le le.
PRId\fIN\fR!PRIdLEAST\fIN\fR!PRIdFAST\fIN\fR!PRIdMAX!PRIdPTR
PRIi\fIN\fR!PRIiLEAST\fIN\fR!PRIiFAST\fIN\fR!PRIiMAX!PRIiPTR
.TE
.RE
.P
The
\fIfprintf\fR()
macros for unsigned integers are:
.sp
.RS
.TS
tab(!);
le le le le le.
PRIo\fIN\fR!PRIoLEAST\fIN\fR!PRIoFAST\fIN\fR!PRIoMAX!PRIoPTR
PRIu\fIN\fR!PRIuLEAST\fIN\fR!PRIuFAST\fIN\fR!PRIuMAX!PRIuPTR
PRIx\fIN\fR!PRIxLEAST\fIN\fR!PRIxFAST\fIN\fR!PRIxMAX!PRIxPTR
PRIX\fIN\fR!PRIXLEAST\fIN\fR!PRIXFAST\fIN\fR!PRIXMAX!PRIXPTR
.TE
.RE
.P
The
\fIfscanf\fR()
macros for signed integers are:
.sp
.RS
.TS
tab(!);
le le le le le.
SCNd\fIN\fR!SCNdLEAST\fIN\fR!SCNdFAST\fIN\fR!SCNdMAX!SCNdPTR
SCNi\fIN\fR!SCNiLEAST\fIN\fR!SCNiFAST\fIN\fR!SCNiMAX!SCNiPTR
.TE
.RE
.P
The
\fIfscanf\fR()
macros for unsigned integers are:
.sp
.RS
.TS
tab(!);
le le le le le.
SCNo\fIN\fR!SCNoLEAST\fIN\fR!SCNoFAST\fIN\fR!SCNoMAX!SCNoPTR
SCNu\fIN\fR!SCNuLEAST\fIN\fR!SCNuFAST\fIN\fR!SCNuMAX!SCNuPTR
SCNx\fIN\fR!SCNxLEAST\fIN\fR!SCNxFAST\fIN\fR!SCNxMAX!SCNxPTR
.TE
.RE
.P
For each type that the implementation provides in
.IR <stdint.h> ,
the corresponding
\fIfprintf\fR()
and
\fIfwprintf\fR()
macros shall be defined and the corresponding
\fIfscanf\fR()
and
\fIfwscanf\fR()
macros shall be defined unless the implementation does not have a
suitable modifier for the type.
.P
The following shall be declared as functions and may also be defined as
macros. Function prototypes shall be provided.
.sp
.RS 4
.nf

intmax_t  imaxabs(intmax_t);
imaxdiv_t imaxdiv(intmax_t, intmax_t);
intmax_t  strtoimax(const char *restrict, char **restrict, int);
uintmax_t strtoumax(const char *restrict, char **restrict, int);
intmax_t  wcstoimax(const wchar_t *restrict, wchar_t **restrict, int);
uintmax_t wcstoumax(const wchar_t *restrict, wchar_t **restrict, int);
.fi
.P
.RE
.LP
.IR "The following sections are informative."
.SH "EXAMPLES"
.LP
.nf
#include <inttypes.h>
#include <wchar.h>
int main(void)
{
    uintmax_t i = UINTMAX_MAX; // This type always exists.
    wprintf(L"The largest integer value is %020"
        PRIxMAX "\en", i);
    return 0;
}
.fi
.SH "APPLICATION USAGE"
The purpose of
.IR <inttypes.h> 
is to provide a set of integer types whose definitions are consistent
across machines and independent of operating systems and other
implementation idiosyncrasies. It defines, through
.BR typedef ,
integer types of various sizes. Implementations are free to
.BR typedef
them as ISO\ C standard integer types or extensions that they support. Consistent
use of this header will greatly increase the portability of applications
across platforms.
.SH RATIONALE
The ISO/IEC\ 9899:\|1990 standard specified that the language should support four signed and
unsigned integer data types\(em\c
.BR char ,
.BR short ,
.BR int ,
and
.BR long \(em\c
but placed very little requirement on their size other than that
.BR int
and
.BR short
be at least 16 bits and
.BR long
be at least as long as
.BR int
and not smaller than 32 bits. For 16-bit systems, most implementations
assigned 8, 16, 16, and 32 bits to
.BR char ,
.BR short ,
.BR int ,
and
.BR long ,
respectively. For 32-bit systems, the common practice has been to
assign 8, 16, 32, and 32 bits to these types. This difference in
.BR int
size can create some problems for users who migrate from one system to
another which assigns different sizes to integer types, because the
ISO\ C standard integer promotion rule can produce silent changes unexpectedly.
The need for defining an extended integer type increased with the
introduction of 64-bit systems.
.SH "FUTURE DIRECTIONS"
Macro names beginning with PRI or SCN followed by any lowercase letter
or
.BR 'X' 
may be added to the macros defined in the
.IR <inttypes.h> 
header.
.SH "SEE ALSO"
.IR "\fB<stddef.h>\fP"
.P
The System Interfaces volume of POSIX.1\(hy2017,
.IR "Section 2.2" ", " "The Compilation Environment",
.IR "\fIimaxabs\fR\^(\|)",
.IR "\fIimaxdiv\fR\^(\|)",
.IR "\fIstrtoimax\fR\^(\|)",
.IR "\fIwcstoimax\fR\^(\|)"
.\"
.SH COPYRIGHT
Portions of this text are reprinted and reproduced in electronic form
from IEEE Std 1003.1-2017, Standard for Information Technology
-- Portable Operating System Interface (POSIX), The Open Group Base
Specifications Issue 7, 2018 Edition,
Copyright (C) 2018 by the Institute of
Electrical and Electronics Engineers, Inc and The Open Group.
In the event of any discrepancy between this version and the original IEEE and
The Open Group Standard, the original IEEE and The Open Group Standard
is the referee document. The original Standard can be obtained online at
http://www.opengroup.org/unix/online.html .
.PP
Any typographical or formatting errors that appear
in this page are most likely
to have been introduced during the conversion of the source files to
man page format. To report such errors, see
https://www.kernel.org/doc/man-pages/reporting_bugs.html .
